1. Android Development
Without Java

2. Android Development
With Scala

3. Scala

4. Scala is

5. Scala is
A Functional

6. Scala is
A Functional
Object Oriented

7. Scala is
A Functional
Object Oriented
Statically Typed

8. Scala is
A Functional
Object Oriented
Statically Typed
Scalable

9. Scala is
A Functional
Object Oriented
Statically Typed
Scalable
Language

10. Scala is
A Functional
Object Oriented
Statically Typed
Scalable
Language
Running on JVM

11. Scala is
A Functional
Object Oriented
Statically Typed
Scalable
Language
Running on JVM and DalvikVM

12. Why Scala

13. Java
public class MyActivity extends Activity {
ListView comments;
Button newComment;
@Override
void onCreate(Bundle bundle) {
super.onCreate(bundle);
comments = (ListView) findViewById(R.id.comments);
newComment = (Button) findViewById(R.id.new_comment);
//...
}
public void sayHello() {
Toast.makeText(this, “Hello”, Toast.LENGTH_LONG).show();
}
}
Initialize context and views

14. Java with RoboGuice
public class MyActivity extends RoboActivity {
@Inject Application context;
@Inject SessionManager sessionManager;
@Inject(R.id.comments) ListView comments;
@Inject(R.id.new_comment) Button newComment;
public void sayHello() {
Toast.makeText(this, “Hello”, Toast.LENGTH_LONG).show();
}
}
Inject views

15. GO HOME ANDROID. YOU ARE DRUNK.

16. Scala
class MyActivity extends ScalaActivity {
lazy val SessionManager
lazy val comments = findView(TR.comments)
lazy val newComment = findView(TR.new_comment)
def sayHello() = “Hello”.toast()
}
Lazily load views
Toast using implicit conversion
Implicit Context

17. A Sample Project

18. shadowsocks

19. shadowsocks
• github/shadowsocks/shadowsocks-android
• written in C/C++ and Scala
• modules
– shadowsocks-libev: secured socks5 proxy in pure C
– shadowsocks-android: UI/Android interface in Scala
– lwIP/tun2socks: user space TCP/IP stack in C++
– pdnsd/iptables/redsocks: native porting for android

20. Project Structure
project/
Build.scala <SBT makefile>
plugins.sbt <SBT plugin config>
src/
main/
res/ <resource files>
assets/ <asset files>
jni/ <native codes>
libs/ <jar and native libraries>
scala/ <main Scala sources>
java/ <main Java sources>
AndroidManifest.xml <manifest template>
test/ <test sources>

21. SBT
• Simple Build Tool for Scala / Java
– Ant, Maven, Gradle like tool in Scala
• github/jberkel/android-plugin
– SBT plugin for Android
– Dependency management, unit test, instrumentation, auto
tasks, etc

22. Components
• UI
– ActionBarSherlock
– SwitchBackport
– Crouton
– UnifiedPreference
– UniversalImageLoader
• Libraries
– DNSJava
– Analytics
– AdMob

23. Components

24. Best Practices
• Proguard
– Aggressive default rules
• IntelliJ IDEA
– Best IDE for Scala and Android
• Continuous Integration
– Travis is best, Jenkins works well

25. Questions?

26. Thanks!

27. About Me
• Max Lv
– Member of Tangcha Project
• 字节社 for Android, http://zijieshe.com
– Major Contributor of GoAgent Project
• github/madeye/gaeproxy
– Core maintainer of Shadowsocks Project
• github/madeye/shadowsocks-libev
• github/shadowsocks/shadowsocks-android